According to Readers Guide to The Mahatma Letters to A. P. Sinnett:
Cook, Rev. Joseph, a Boston preacher who at one time supported the idea of spiritualism but when he went to India in 1882, he denounced both spiritualism and Theosophy. Damodar countered his accusations in the press. M calls him "a pump of filth" (ML, p. 267). There is a newspaper clipping about him in HPB's scrapbook. ODL 2: 329; D, pp. 178-80; SH index.
- George E. Linton and Virginia Hanson, eds., Readers Guide to The Mahatma Letters to A. P. Sinnett (Adyar, Chennai, India: Theosophical Publishing House, 1972), 219.